The invention relates to a shielding device for a plug connector of a backplane printed circuit board of a mounting rack. The shielding device along the side walls of a plug housing has shielding metal sheets which are perpendicular to the backplane printed circuit board and are connected to a shielding layer of the backplane printed circuit board.
A shielding device of this type has been disclosed, for example, by the documents of German Utility Model 92 05 780.2. According to this document, the shielding metal sheets are provided with pin-like projections which can be pressed into holes in the printed circuit board. It is customary to design these holes as plated-through holes connected to the ground layers of the printed circuit board. This produces a close shielding contact between the shielding metal sheet and the ground layers.
The shielding metal sheets have a multiplicity of spring tongues which are upright in the insertion direction and can be connected to a shielding housing of a plug-on mating plug. The spring tongues are formed by being stamped from the shielding metal sheet and bent out towards the side walls of the plug housing. Perforations, which can impair the shielding effect of the shielding metal sheet, are produced in this case in the shielding metal sheet. However, there is also produced between the shielding metal sheet and the outer wall of the plugged-on shielding housing a gap which can reduce the shielding effect still further.